This is the seventh edition of a book which has been for years the 'bible' of professional and amateur gemmologists, as well as retail jewellers. Originally written by Robert Webster, an expert who dedicated most of his life to the subject and who worked in the London Gem Testing Laboratory for twenty-five years, this edition has been completely revised and updated by E. Alan Jobbins, Keeper of Minerals and Gemstones at the Geological Museum in London for thirty-five years. The first part of the book is a comprehensive glossary on all aspects of gemstones and the terms associated with them. The second part includes sections on manufactured gems, the enhancement of gem materials and on the precautions necessary for avoiding damage to gemstones and jewellery during manufacturing, repairs and cleaning. There are comprehensive sets of tables of the physical constraints needed for gem testing, of the sources of gem materials and the cuts used to demonstrate their beauty. Fifteen pages of colour photographs will assist in the identification of inclusions and there are many useful conversion tables.

Gemmological Instruments deals with the developments in diamond grading equipment and gem testing instruments since the publication of the first edition in 1978. These developments include improvements in the versatility and styling of existing instruments such as the reflectivity meter, the composite spectroscope, and the refractometer. It also addresses the criticisms in the first edition and provides a discussion of the advantages and disadvantages of different gem testing equipment. This book is organized into 16 chapters that describe groundbreaking instruments like the thermal conductivity diamond testers and home-constructed items that while innovative have not yet been commercialized. There are also chapters dealing with microphotography and identification of synthetics and stimulants. This book also provides a listing of gemstone constants and characteristic inclusions in natural and synthetic gemstones. This book will be of interest to people interested in equipment for gem testing and diamond grading.